Build material particle fusing in a chamber containing vapor

ABSTRACT

According to an example, an apparatus may include an agent delivery device to selectively deliver an agent onto a layer of build material particles. The apparatus may also include an energy source to apply energy onto the layer of build material particles to selectively fuse the build material particles in the layer based upon the locations at which the agent was delivered and a chamber formed of a plurality of walls, in which the agent delivery device and the energy source are housed inside the chamber. The apparatus may further include a vapor source to supply vapor into the chamber to wet the build material particles inside the chamber.

BACKGROUND

3D manufacturing apparatuses that employ additive manufacturingtechniques to build or print parts are gaining in popularity and use.Some additive manufacturing techniques employ a layering process inwhich particles of build material are spread into a layer andselectively fused together. Following that process, additional particlesare spread into another layer and selectively fused together. Thisprocess is repeated for a number of times to build up a 3D part having adesired configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

Features of the present disclosure are illustrated by way of example andnot limited in the following figure(s), in which like numerals indicatelike elements, in which:

FIGS. 1A and 1B respectively show simplified block diagrams of exampleapparatuses that may include components to selectively fuse buildmaterial particles in the presence of vapor;

FIG. 2 shows a simplified block diagram of an example three-dimensional(3D) printer that may include printing components and a vapor supplysystem;

FIG. 3 shows a simplified block diagram of another example apparatusthat may be implemented to supply vapor during a 3D part formingprocess;

FIG. 3 shows a simplified block diagram of another example apparatus;and

FIG. 4 depicts a flow diagram of an example method for printing a 3Dobject from build material particles in a chamber supplied with vapor.

DETAILED DESCRIPTION

Disclosed herein are apparatuses and methods for forming 3D printedparts in a chamber into which vapor may be supplied. Particularly,disclosed herein are apparatuses and methods in which build materialparticles are fused together inside of a chamber while vapor is suppliedonto the build material particles to wet the build material particlesduring the fusing process. In some examples, the vapor may be sprayeddirectly onto the build material particles prior to fusing operationsbeing performed on the build material particles.

Wetting of the build material particles with vapor as disclosed hereinmay reduce displacement of the build material particles from layers ofbuild material particles, which may reduce entry of the build materialparticles into the slots of fluid or agent delivery devices of a 3Dprinter. As such, wetting of the build material particles with vapor mayreduce clogging of the delivery device slots, which may improvefunctioning and the life spans of the delivery devices. In anotherregard, wetting of the build material particles may reduce local hotspots in the layer of build material particles, which may result inimproved 3D part building quality. In another regard, wetting of thebuild material particles with vapor as disclosed herein may reduce thepotential for the build material particles from catching fire orexploding, which may occur with the dry build material particles due totheir small sizes and exposure to high temperatures during the 3D partfabrication processes. In a further regard, wetting of the buildmaterial particles with vapor as disclosed herein may reduceelectrostatic interactions between the particles as the vapor may helpto discharge the electrostatic charges that may otherwise form betweenthe particles. Discharging the electrostatic charges between theparticles may reduce adhesion between the particles, which may assist inthe ability to reuse or recycle unfused particles.

Before continuing, it is noted that as used herein, the terms “includes”and “including” mean, but are not limited to, “includes” or “including”and “includes at least” or “including at least.” The term “based on”means, but is not limited to, “based on” and “based at least in parton.”

FIGS. 1A and 1B respectively show simplified block diagrams of exampleapparatuses 100, 150 that may include components to selectively fusebuild material particles in the presence of vapor. It should beunderstood that the apparatuses 100, 150 depicted in FIGS. 1A and 1B mayinclude additional components and that some of the components describedherein may be removed and/or modified without departing from the scopesof the apparatuses 100, 150 disclosed herein.

With reference first to FIG. 1A, the apparatus 100 may include an agentdelivery device 102 that may selectively deliver an agent 104 onto alayer of build material particles 106. In various examples, the agentdelivery device 102 may be a printhead having actuators, e.g., thermalinkjet resistors, piezoelectric actuators, or the like, to eject theagent 104 from firing chambers for selective delivery of the agent 104onto the build material particles 106 and the agent 104 may be anprinting liquid. By way of particular example, the agent 104 may be afusing agent, a detailing agent, etc. Particularly, a fusing agent maybe a substance that is to absorb fusing radiation (e.g., in the form oflight and/or heat) to cause the build material particles 106 upon whichthe fusing agent has been deposited to fuse together when fusingradiation is applied onto the fusing agent and the build materialparticles 106. A detailing agent may be a substance that may absorbsignificantly less of the fusing radiation as compared with the fusingagent. In one example, the detailing agent may prevent or significantlyreduce the fusing together of the build material particles 106 uponwhich the detailing agent has been deposited during application offusing radiation onto the detailing agent and the build materialparticles 106.

In examples in which the agent 104 is a fusing agent, the agent deliverydevice 102 may be controlled to deliver the agent 104 onto the buildmaterial particles 106 that are located in areas of the layer that areto be fused together. In examples in which the agent 104 is a detailingagent, the agent delivery device 102 may be controlled to deliver theagent 104 onto build material particles 106 that are located in areas ofthe layer that are to remain unfused from each other. In other examples,the agent delivery device 102 may include multiple delivery devices, inwhich one of the delivery devices may deliver a fusing agent and anotherone of the delivery devices may deliver a detailing agent. In anyregard, 3D objects or parts may be generated from the build materialparticles 106 and the build material particles 106 may be formed of anysuitable material including, but not limited to, polymers, metals, andceramics. In addition, the build material particles 106 may be in theform of a dry powder.

The apparatus 100 may also include an energy source 108 that is to applyenergy 110 onto the layer of build material particles 106 to selectivelyfuse the build material particles 106 in the layer based upon thelocations at which the agent 104 was delivered. That is, followingdeposition of the agent 104 onto selected areas of the layer of buildmaterial particles 106, the energy source 108 may be implemented toapply energy 110, e.g., fusing radiation, onto the build materialparticles 106. Particularly, for instance, the energy source 108 may beactivated and moved across the layer of build material particles 106 toapply fusing radiation in the form of light and/or heat onto the buildmaterial particles 106. Examples of the energy source 108 may include aUV, IR or near-IR curing lamp, an IR or near-IR light emitting diode(LED), a halogen lamp emitting in the visible and near-IR range, or alaser with desirable electromagnetic wavelengths. According to anexample, the agent delivery device 102 and the energy source 108 may besupported on a carriage (not shown) that may be scanned over the layerof build material particles 106 to enable the agent 104 to be depositedand the energy 110 to be applied over most of the layer of buildmaterial particles 106.

In examples in which the agent 104 is a fusing agent, application of theenergy 110 may result in the build material particles 106 upon which theagent 104 has been deposited to be heated above their meltingtemperatures through enhancement of heat absorption by the fusing agent.These build material particles 106 may thus melt and may fuse togetherwhen cooled. In examples in which the agent 104 is a detailing agent,application of the energy 110 may result in the build material particles106 upon which the agent 104 has been deposited to remain below theirmelting temperatures through limiting of heat absorption by thedetailing agent. In these examples, the energy 110 may be of sufficientstrength to cause the build material particles 106 that have notreceived the detailing agent to melt and subsequently fuse together.

The apparatus 100 may further include a chamber 112 formed of aplurality of walls. According to examples, the chamber 112 may be sealedfrom an external environment or may partially be sealed from theexternal environment. Thus, for instance, the chamber 112 may have sixsides, e.g., four walls, a floor, and ceiling, in which each of thesides may be closed or partially open. In any regard, the agent deliverydevice 102, the build material particles 106, and the energy source 108may be housed inside the chamber 112.

According to examples, the interior of the chamber 112 may be suppliedwith a vapor 114. The vapor 114 may be water vapor (e.g., steam), a gas(e.g., a noble gas), or the like. In addition or in other examples, thevapor 114 may be composed of particles of a non-caustic andnon-corrosive material. Thus, for instance, the vapor 114 may preventoxidation of the components housed in the chamber 112. In still otherexamples, the vapor 114 may include reagents that may provide additionaleffects on the build material particles 106, e.g., control othermaterial properties of the fused build material particles 106. The vapor114 may also be at a temperature that is near the temperature at whichthe build material particles 106 are maintained prior to application ofenergy 110 by the energy source 108 such that that vapor 114 does notsignificantly prevent or hinder selective fusing of the build materialparticles 106. Additionally, the vapor 114 may be cooler than local hotspots that may form in the layer of build material particles 106 andthus, the vapor 114 may act to remove the local hot spots.

In any case, the vapor 114 may be supplied into the chamber 112 to wetthe build material particles 106. In the example shown, the vapor 114may be supplied into the chamber 112 above the agent delivery device 102and the energy source 108. In this example, the agent delivery device102 and the energy source 108 may be moved such that the agent deliverydevice 102 and the energy source 108 are not directly between thenozzles 116 and the layer of build material particles 106 duringapplication of the vapor 114 on the layer of build material particles106. In other examples, the nozzles 116 may be positioned between theagent delivery device 102 and the energy source 108 and the layer ofbuild material particles 106 or adjacent to the agent delivery device102. In these examples, the nozzles 116 may be provided on a movabledevice such that the nozzles 116 may be moved out of the way of theagent delivery device 102 and the energy source 108 during agentdelivery and energy application processes. By way of particular example,the vapor 114 may be supplied onto the build material particles 106 eachtime a new layer of build material particles 106 is formed and prior todelivery of agent and application of fusing energy.

In one regard, wetting the build material particles 106 with the vapor114 may reduce displacement of the build material particles 106 from thelayer, which may reduce entry of the build material particles 106 intoslots in the agent delivery device 102 through which an agent 104 isdelivered. As such, wetting the build material particles 106 with thevapor 114 may reduce clogging of the agent delivery device 102 slots,which may improve functioning and the life of the agent delivery device102. In another regard, wetting the build material particles 106 withthe vapor 114 may reduce the potential for the build material particles106 from catching fire or exploding, which may occur with dry particles106 due to their small sizes, e.g., between about 20 microns to about 80microns, and exposure to high temperatures, e.g., over 160° C., duringthe 3D part fabrication processes. In a further regard, wetting thebuild material particles 106 with the vapor 114 may reduce electrostaticinteractions between the particles 106 as the vapor 114 may help todischarge the electrostatic charges that may otherwise form between theparticles 106. Discharging the electrostatic charges between theparticles 106 may reduce adhesion between the particles 106, which mayassist in the ability to reuse or recycle unfused particles 106.

As further shown in FIG. 1A, the vapor 114 may be supplied into thechamber 112 through a plurality of nozzles 116. The nozzles 116 maysupply the vapor 114 into the chamber 112 in the form of a spray or amist. In addition, the vapor 114 may be supplied to the nozzles 116through a conduit 118, which may be in fluid communication with a vaporsource 120. The vapor source 120 may be a boiler or other device that isto vaporize a liquid material 122. The vapor source 120 may also includea compressor such that the chamber 112 may become pressurized throughintroduction of the vapor 114 into the chamber 112, for instance, whenthe chamber 112 is closed or semi-closed.

Turning now to FIG. 1B, the apparatus 150 may include many of the samecomponents as the apparatus 100 depicted in FIG. 1A. As such, the commoncomponents are not described again in detail with respect to FIG. 1B.Instead, it should be understood that the descriptions of the commonelements provided above with respect to FIG. 1A are intended to alsodescribe those elements with respect to FIG. 1B.

In the apparatus 150, the agent delivery device 102 and the energysource 108 are depicted as being positioned away from the layer of buildmaterial particles 106. That is, the agent delivery device 102 and theenergy source 108 may be movable as indicated by the arrow 152 betweenpositions in which the agent delivery device 102 deposits on and doesnot deposit on the layer of build material particles 106 and the energysource 108 applies energy on and does not apply energy on the layer ofbuild material particles 106. In one regard, the agent delivery device102 and the energy source 108 may be moved away from the layer of buildmaterial particles 106 between printing/heating passes, during formationof additional layers of build material particles 106, during cleaningoperations of the agent delivery device 102, etc.

In some examples, including the example depicted in FIG. 1B, the agentdelivery device 102 and the energy source 108 may be moved away from thelayer of build material particles 106 to enable vapor 114 to be directlyapplied onto the layer of build material particles 106. That is, forinstance, while the agent delivery device 102 and the energy source 108are moved away from the layer of build material particles 106, thenozzles 116 may be positioned in relatively close proximity to the layerof build material particles 106 and vapor 114 may be sprayed directlyonto the layer of build material particles 106. By way of example, thevapor 114 may be sprayed onto each new layer of build material particles106, e.g., between successive printing/fusing operations. In otherexamples, the vapor 114 may be sprayed onto the layer of build materialparticles 106 after a predetermined number of layers have been formed,e.g., between a certain number of printing/fusing operations.

In any regard, a section 154 of the conduit 118 containing the nozzles116 may be movable such that the section 154 of the conduit 118 may bemoved away from the layer of build material particles 106. In thisregard, the section 154 of the conduit 118 may be connected to theremaining section of the conduit 118 via a movable, e.g., rotatable,translatable, etc., connector 156. The connector 156 may enable thesection 154 to be moved in the x, y, or z directions with respect to thelayer of build material particles 106. With the section 154 moved, theagent delivery device 102 and the energy source 108 may be moved overthe layer of build material particles 106 as discussed herein.

According to examples, the connector 156 may be a motorized connectorthat a controller 158 may control along with the agent delivery device102 and the energy source 108. The controller 156 may be a computingdevice, a semiconductor-based microprocessor, a central processing unit(CPU), an application specific integrated circuit (ASIC), a graphicsprocessing unit (GPU), a field programmable gate array (FPGA) and/orother hardware device. The controller 156 may be part of the apparatus150 or may be separate from the apparatus 150.

The controller 156 may also control a valve 160 that may variablycontrol delivery of the vapor 114 from the vapor source 120 to theinterior of the chamber 112. For instance, through control of the valve160, the controller 156 may control the volume of vapor 114 beingsupplied to the nozzles 116, the timing at which the vapor 114 issupplied to the nozzles 116, the pressure inside the chamber 112, etc.By way of example, the controller 156 may control the valve 160 to ceasedelivery of the vapor 114 to the nozzles 116 when the section 154 of theconduit 118 is moved away from the layer of build material particles106. The controller 156 may additionally or in other examples ceasedelivery of the vapor 114 to the nozzles 116 when the pressure insidethe chamber 112 reaches a certain level.

The apparatus 150 may further include a liquid collection system 170 tocollect liquid from a bottom of the chamber 112 and a vapor collectionsystem 180 to collect excess vapor 114 from the chamber 112. The liquidcollection system 170 may collect vapor 114 that has condensed andreached the bottom of the chamber 112. The liquid collection system 170may direct the collected liquid to a location at which the collectedliquid may be discarded as indicated by the arrow 172. In addition orother examples, the arrow 172 may denote the return of the collectedliquid to the vapor source 120. The vapor collection system 180 maycollect excess vapor 114 from a ceiling of the chamber 112. The vaporcollection system 180 may include a valve (not shown) to control thevolume of vapor 114 collected from the chamber 112. The vapor collectionsystem 180 may be implemented to remove vapor 114 from the chamber 112,for example, in instances in which the pressure inside the chamber 112exceeds a predetermined pressure level through control of a valve (notshown). The vapor collection system 180 may direct collected vapor 114may direct the collected vapor 114 to a location at which the collectedvapor 114 may be discarded as indicated by the arrow 182. In addition orother examples, the arrow 182 may denote the return of the collectedvapor 114 to the vapor source 120. In one regard, the vapor 114 and/orthe condensed vapor 114 may be collected and removed from the chamber112 and may be re-used in the chamber 112. Although not shown, a pump orpumps may be provided to assist in moving the vapor 114 and/or condensedvapor 114 away from the chamber 112.

With reference now to FIG. 2, there is shown a simplified block diagramof an example three-dimensional (3D) printer 200 that may includeprinting components and a vapor supply system. It should be understoodthat the 3D printer 200 may include additional components and that someof the components described herein may be removed and/or modifiedwithout departing from a scope of the 3D printer 200 disclosed herein.

The 3D printer 200 may include a build area platform 202, a buildmaterial supply 204 containing build material particles 206, and arecoater 208. The build material supply 204 may be a container orsurface that is to position build material particles 206 between therecoater 208 and the build area platform 202. Generally speaking, 3Dobjects or parts are to be generated from the build material particles206 and the build material particles 206 may be formed of any suitablematerial including, but not limited to, polymers, metals, and ceramics.In addition, the build material particles 206 may be in the form of apowder and may thus also be considered to be build material powder 206.

The recoater 208 may move in a direction as denoted by the arrow 210,e.g., along the y-axis, over the build material supply 204 and acrossthe build area platform 202 to spread a layer 212 of the build materialparticles 206 over a surface of the build area platform 202. Therecoater 208 may also be returned to a position adjacent the buildmaterial supply 204 following the spreading of the build materialparticles 206. The recoater 208 may be a doctor blade, roller, a counterrotating roller or any other device suitable for spreading the buildmaterial particles 206 over the build area platform 202. According toexamples, the build area platform 202 may be heated to apply heat ontospread layers 212 of the build material particles 206.

According to examples, the 3D printer 200 may include an agent deliverydevice 214 and an energy source 216, which may both be scanned acrossthe build area platform 202 in both of the directions indicated by thearrow 218, e.g., along the x-axis. The agent delivery device 214 may be,for instance, a thermal inkjet printhead, a piezoelectric printhead, orthe like, and may extend a width of the build area platform 202. Theagent delivery device 214 may be equivalent to the agent delivery device102 discussed above. In other examples in which the agent deliverydevice 214 does not extend the width of the build area platform 202, theagent delivery device 214 may also be scanned along the y-axis to thusenable the agent delivery device 214 to be positioned over a majority ofthe area above the build area platform 202. The agent delivery device214 may be attached to a moving XY stage or a translational carriage(neither of which is shown) that is to move the agent delivery device214 adjacent to the build area platform 202 in order to deposit theagent or agents in predetermined areas of a layer of the build materialparticles 206. Various examples of the agents are discussed above.

Following deposition of the agent onto selected areas of the layer 212of the build material particles 206, the energy source 216 may beimplemented to apply fusing radiation onto the build material particles206 in the layer 212. Particularly, for instance, the energy source 216may be activated and moved across the layer 212, for instance, along thedirections indicated by the arrow 218, to apply fusing radiation in theform of light and/or heat onto the build material particles 206. Theenergy source 216 may be equivalent to the energy source 108 discussedabove with respect to FIGS. 1A and 1B. According to examples, the agentdelivery device 214 and the energy source 216 may be supported on acarriage (not shown) that may be scanned over the build area platform202 in the directions denoted by the arrow 218.

In other examples, the agent delivery device 214 may be omitted and theenergy source 216 may directly fuse the build material particles 206 ina selective manner. In these examples, the energy source 216 may emit alaser beam onto the build material particles 206 in selected locationsof the layer 212 to selectively fuse the build material particles 206 inthose selected locations. In this regard, the 3D printer 200 may performselective laser sintering (SLS), selective laser melting (SLM),electron-beam melting (EBM), Selective Inhibition Sintering (SIS), orthe like. Generally speaking, the 3D printer 200 may perform 3D printingusing any suitable powder-based fusing techniques.

In any of the examples above, following application of the energy, e.g.,radiation, to fuse selected sections of the build material particles 206together, the build area platform 202 may be lowered as denoted by thearrow 220, e.g., along the z-axis. In addition, the recoater 208 may bemoved across the build area platform 202 to form a new layer 212 ofbuild material particles 206 on top of the previously formed layer.Moreover, another build material particle 206 fusing operation may beperformed on the new layer 212. The above-described process may berepeated until a predetermined number of layers have been formed tofabricate a green body of a desired 3D part.

According to examples, the build area platform 202, the recoater 208,and the energy source 216 may be housed within a chamber 222 formed of aplurality of walls 224. A mechanism (not shown) to move the build areaplatform 202 may be contained inside the chamber 222 and/or may extendthrough a wall 224 of the chamber 222. The chamber 222 may be similar tothe chamber 112 depicted in FIGS. 1A and 1B. In addition, vapor may bedelivered through a conduit (represented by the arrow 226) into thechamber 222 from a vapor source 228 through an opening 230 in one of thewalls 224 of the chamber 222. The conduit 226 may supply the vapor to aplurality of nozzles 232 that may be positioned above the build areaplatform 202 in any suitable manner. The nozzles 232 may be positionedin manners similar to those discussed above with respect to FIGS. 1A and1B. As such, the nozzles 232 may be stationary or may be movable and maysupply vapor onto the build material particles 206 in the layer 212. Inaddition, the vapor source 228 may include a compressor and/or a valveas discussed above with respect to FIGS. 1A and 1B. Moreover, a liquidcollection system 170 and/or a vapor collection system 180 as shown inFIG. 1B may be connected to the chamber 222.

As further shown in FIG. 2, the 3D printer 200 may include a controller240 that may control operations of the build area platform 202, thebuild material supply 204, the recoater 208, the agent delivery device214, the energy source 216, and the vapor source 228. The controller 240may also control operations of a compressor and/or valve. The controller240 may control actuators (not shown) to control various operations ofthe 3D printer 200 components and the vapor supply system (e.g., thevapor source 228, the valve, the nozzles, etc.). The controller 240 maybe a computing device, a semiconductor-based microprocessor, a centralprocessing unit (CPU), an application specific integrated circuit(ASIC), a graphics processing unit (GPU), a field programmable gatearray (FPGA), and/or other hardware device. Although not shown, thecontroller 240 may be connected to the 3D printer 200 components and thevapor supply system via communication lines.

The controller 240 may be in communication with a data store 242. Thedata store 242 may include data pertaining to a 3D part to be printed bythe 3D printer 200. For instance, the data may include the locations ineach build material layer 212 that are to be fused together to form thegreen body of the 3D part. In one example, the controller 240 may usethe data to control the locations on each of the build material layers212 that the agent delivery device 214 deposits the agent. Additionally,the controller 240 may control when the vapor is delivered into thechamber 222.

Turning now to FIG. 3, there is shown a simplified block diagram ofanother example apparatus 300 that may be implemented to supply vaporduring a 3D part forming process. It should be understood that theapparatus 300 depicted in FIG. 3 may include additional components andthat some of the components described herein may be removed and/ormodified without departing from a scope of the apparatus 300 disclosedherein.

The apparatus 300 may include a controller 302 that may controloperations of the apparatus 300 and a data store 304 that may store datathat is accessible by the controller 302. The controller 302 may be asemiconductor-based microprocessor, a central processing unit (CPU), anapplication specific integrated circuit (ASIC), field-programmable gatearray (FPGA), a graphics processing unit (GPU), and/or other hardwaredevice. The apparatus 300 may also include a memory 310 that may havestored thereon machine readable instructions 312-316 (which may also betermed computer readable instructions) that the controller 302 mayexecute. The memory 310 may be an electronic, magnetic, optical, orother physical storage device that contains or stores executableinstructions. The memory 310 may be, for example, Random Access Memory(RAM), an Electrically Erasable Programmable Read-Only Memory (EEPROM),a storage device, an optical disc, and the like. The memory 310, whichmay also be referred to as a computer readable storage medium, may be anon-transitory machine-readable storage medium, where the term“non-transitory” does not encompass transitory propagating signals.

The apparatus 300 may be a computing device such as a personal computer,a laptop computer, a smartphone, a server computer, a tablet computer,or the like. In other examples, the apparatus 300 may be or form part ofa 3D printer. The controller 302 may communicate instructions to 3Dprinter components 320 and vapor supply components 330 over a network,through a wired connection, a bus, or the like. The 3D printercomponents 320 may include the components shown in the 3D printer 200depicted in FIG. 2, such as a build area platform 202, a recoater 208,an energy source 216, etc. The vapor supply components 330 may alsoinclude the components shown in the 3D printer 200 depicted in FIG. 2,such as a vapor source 228, a valve, nozzles 232, etc. As discussedabove with respect to FIG. 2, the 3D printer components 320 may behoused in a chamber 222.

With reference to FIGS. 1A-3, the controller 302 may fetch, decode, andexecute the instructions 312 to supply vapor into the chamber 222. Thatis, for instance, the controller 302 may activate the vapor source 228,open a valve 160, open the nozzles 116, 118, or the like, to supplyvapor into the chamber 222. The controller 302 may fetch, decode, andexecute the instructions 314 to move the recoater 208 over a build areaplatform 202 to form a layer 212 of build material particles 206.According to examples, the vapor may be supplied directly onto a layer212 of build material particles 206 or generally into the chamber 222.The controller 302 may fetch, decode, and execute the instructions 316to selectively fuse the build material particles 206 in the formed layer212. That is, for instance, the controller 302 may control the energysource 216 to apply energy onto the build material particles 206 inselected areas of the layer 212. In addition or in other examples, thecontroller 302 may control the agent delivery device 214 to deliver anagent to the build material particles 206 in selected areas of the layer212 and the energy source 216 to apply energy onto the layer 212 ofbuild material particles 206.

Various manners in which the apparatus 300 may be implemented arediscussed in greater detail with respect to the method 400 depicted inFIG. 4. Particularly, FIG. 4 depicts a flow diagram of an example method400 for printing a 3D object from build material particles in a chambersupplied with vapor. It should be understood that the method 400depicted in FIG. 4 may include additional operations and that some ofthe operations described therein may be removed and/or modified withoutdeparting from the scope of the method 400. The description of themethod 400 is made with reference to the features depicted in FIGS. 1A-3for purposes of illustration. Generally speaking, the controller 302 ofthe apparatus 300 may implement or execute some or all of theinstructions 312-316 stored on the memory 310 to perform the method 400.However, it is contemplated that other computing devices may implementor perform the operations described with respect to the method 400.

At block 402, a recoater 208 may be moved over a build area platform 202to form a layer 212 of build material particles 206. The recoater 208and the build area platform 202 may be housed in chamber 112, 222. Inother examples, an agent delivery device 214, and the like, may also behoused in the chamber 112, 222.

At block 404, vapor 114 may be supplied into the chamber 112, 222, inwhich the vapor 114 is to wet the layer 212 of build material particles206. The chamber 112, 222 may house a recoater 208 and an energy source216. The vapor 114 may be supplied into the chamber 112, 222 and in someexamples, directly onto the build material particles 206 in any of themanners discussed above.

At block 406, the build material particles 206 in the layer 212 may beselectively fused. That is, the build material particles 206 in certainlocations of the layer 212 that are to form sections of a 3D printedpart may be fused together. As discussed above, the build materialparticles 206 in the certain locations may be fused together throughapplication of fusing energy onto the build material particles 206.Application of the fusing energy may be with or without priorapplication of the agent as also discussed above.

At block 408, a determination may be made as to whether the method 400is to continue. A determination to continue the method 400 may be madeif build material particles 206 in additional layers 212 are to be fusedtogether to form the 3D part. In response to a determination that themethod 400 is to continue, blocks 402-408 may be repeated to selectivelyfuse the build material particles 206 in additional layers 212 whilebeing supplied with vapor 114. In response to a determination that themethod 400 is not to be continued, the method 400 may end as indicatedat block 410.

Some or all of the operations set forth in the method 400 may becontained as utilities, programs, or subprograms, in any desiredcomputer accessible medium. In addition, the method 400 may be embodiedby computer programs, which may exist in a variety of forms both activeand inactive. For example, they may exist as machine readableinstructions, including source code, object code, executable code orother formats. Any of the above may be embodied on a non-transitorycomputer readable storage medium.

Examples of non-transitory computer readable storage media includecomputer system RAM, ROM, EPROM, EEPROM, and magnetic or optical disksor tapes. It is therefore to be understood that any electronic devicecapable of executing the above-described functions may perform thosefunctions enumerated above.

Although described specifically throughout the entirety of the instantdisclosure, representative examples of the present disclosure haveutility over a wide range of applications, and the above discussion isnot intended and should not be construed to be limiting, but is offeredas an illustrative discussion of aspects of the disclosure.

What has been described and illustrated herein is an example of thedisclosure along with some of its variations. The terms, descriptionsand figures used herein are set forth by way of illustration only andare not meant as limitations. Many variations are possible within thespirit and scope of the disclosure, which is intended to be defined bythe following claims—and their equivalents—in which all terms are meantin their broadest reasonable sense unless otherwise indicated.

What is claimed is:
 1. An apparatus comprising: an agent delivery deviceto selectively deliver an agent onto a layer of build materialparticles; an energy source to apply energy onto the layer of buildmaterial particles to selectively fuse the build material particles inthe layer based upon the locations at which the agent was delivered; achamber formed of a plurality of walls, wherein the agent deliverydevice and the energy source are housed inside the chamber; and a vaporsource to supply vapor into the chamber to wet the build materialparticles inside the chamber.
 2. The apparatus according to claim 1,wherein the vapor source further comprises a plurality of nozzles thatare to spray the vapor directly onto the layer of build materialparticles.
 3. The apparatus according to claim 1, further comprising: avalve to variably control delivery of the vapor into the chamber fromthe vapor source; and a controller to control the valve.
 4. Theapparatus according to claim 1, further comprising: a recoater to spreadthe build material particles into the layer of build material particlesprior to delivery of the agent onto the layer of build materialparticles, wherein the recoater is housed inside the chamber.
 5. Theapparatus according to claim 1, wherein the build material particles aremaintained at a certain temperature prior to application by the energysource of energy onto the build material particles and wherein the vaporsource is to supply the vapor at a temperature that is near the certaintemperature.
 6. The apparatus according to claim 1, wherein the vaporsource includes a compressor to pressurize the vapor being supplied intothe chamber.
 7. The apparatus according to claim 1, further comprising:a liquid collection system to collect liquid from the chamber; and avapor collection system to collect excess vapor from the chamber.
 8. Theapparatus according to claim 1, wherein the vapor is composed ofparticles of a non-caustic and non-corrosive material.
 9. Athree-dimensional (3D) printer comprising: a build area platform; arecoater to spread build material powder into layers over the build areaplatform; an energy source to apply energy onto the spread layers ofbuild material powder to selectively fuse the build material particlesand fabricate a 3D object; and a chamber formed of a plurality of walls,wherein the build area platform, the recoater, and the energy source arehoused inside the chamber, and wherein the chamber is to receive vaporfrom a vapor source and the vapor is to wet the build material powderinside the chamber during fabrication of the 3D object.
 10. The 3Dprinter according to claim 9, further comprising: an agent deliverydevice to selectively deposit an agent onto the spread layers of buildmaterial powder, wherein application of energy by the energy source isto selectively fuse the build material powder based upon the locationsat which the agent has been deposited.
 11. The 3D printer according toclaim 9, further comprising: a plurality of nozzles positioned to supplythe received vapor directly onto the spread layers of build materialpowder.
 12. The 3D printer according to claim 9, wherein the chamber issealed from an ambient environment outside of the chamber.
 13. A methodcomprising: moving a recoater over a build area platform to form a layerof build material particles, wherein the recoater and the build areaplatform are housed in a chamber; supplying vapor into the chamber,wherein the supplied vapor is to wet the layer of build materialparticles; and moving an energy source over the layer of build materialparticles within the chamber to selectively fuse the build materialparticles in the layer.
 14. The method according to claim 13, whereinmoving the recoater further comprises moving the recoater over the buildarea platform to form a plurality of build material particle layers, andwherein supplying vapor into the chamber further comprises supplyingvapor into the chamber between formation of successive build materialparticle layers.
 15. The method according to claim 13, wherein supplyingvapor into the chamber further comprises spraying the vapor directlyonto the layer of build material particles.